The Audiology Clinic is now acting as associate investigator on six protocols (five in other ICDs) as well as continuing to provide the long standing, highly visible support and service collaborations with many branches, sections and units within most institutes of the NIH. This reporting period has seen our continued involvement with the Inter- Institute Genetics Program. In addition to data supplied to other principal investigators and the service component, the Clinical Audiology Unit develops data on hearing and auditory/vestibular system function in diverse disease processes. This year the major clinical research effort has been developing and implementing the audiological part of the NIDCD's Waardenburg protocol wherein we are investigating auditory/vestibular function in patients with the two known forms of Waardenburg. In addition, we are evaluating first degree relatives and family members at risk for Waardenburg in an effort to define and describe auditory phenotypic characteristics in this autosomal dominant disorder. This year we have been very active in the study of Neurofibromatosis Type 2 (NF2) in both affected and at-risk individuals; and our investigation into auditory system function in recessively inherited neurodegenerative metabolic disorders in children (especially Gaucher's Type III and Niemann-Pick C) has been extremely successful. We have been involved in 4 different AIDS protocols, two each with NIAID (adults) and NCI (pediatric). Our patient care or protocol support for patients enrolled in Alzheimer's Disease studies continues as does our role in monitoring ototoxic effects of chemotherapeutic regimens in various cancers and our study of hearing and auditory function in conditions producing iron overload such as Thalassemia. In addition, we have begun to study the auditory system in Eosinophilial Myalgia Syndrome arising from contaminated L-Tryptophan. Formal presentations and publications from several of the foregoing are produced. The assessment of auditory function is achieved through detailed study of puretone and speech sensitivity; suprathreshold studies of speech recognition; biomechanical measurement of middle ear function, including multi-frequency typanometry and electrophysiologic study of auditory evoked potentials. Test strategies are developed for each disorder, condition or therapeutic regimen to elicit the appropriate information for each target population. Additional studies including cochlear emissions, electrocochleography and studies of dichotic function are added to the test battery for certain populations as normative data on these new clinical tools is developed. There continues to be a paucity of audiologic data in the published biomedical literature on many of the diverse diseases and conditions seen here at the NIH. In our efforts to provide new audiologic data on these conditions, this protocol not only improves patient care and quality of life, it responds to the charge of the NIDCD to find, define and manage causes of deafness and hearing impairment. It provides enhanced knowledge regarding the broad role of the auditory system in many diseases. In some cases, specific auditory system dysfunction may signal changes in other organ systems and thereby serve as a reliable screening method in certain recessively inherited conditions for which no biological marker is available. Furthermore, these efforts tend to find entire populations of individuals who have not been previously considered in the epidemiology of deafness and hearing impairment.